Bushings typically include a conductor surrounded by insulation material and have applications, e.g., in high-voltage apparatuses such as generators, reactors or transformers, or in high voltage installations such as gas-insulated switchgears or as test bushings.
A bushing can be a condenser-type bushing which includes an arrangement of metallic layers in the insulation material for controlling the electric field of the bushing. Bushings can include electric connections, e.g. electric circuitry, between such conductive layers and external components of the bushing, such as a voltage measuring tap. The electric connections are often soldered. The connections of the bushing should be checked, e.g. after the design life of the bushing has been exceeded, in order to maintain reliability and availability.
Known methods for testing the quality of electric connections of a bushing are based on real-life operating conditions of the bushing. Such methods can be designed for distinguishing whether an electric connection is functioning properly. However, there is a continuous need for improving such testing methods, so that the reliability of the connection can be ensured to a maximum and the functionality of the connection can be guaranteed for a long-term period of operation.
Accordingly, there is a need for an improved method for testing the quality of the electric connections in a bushing.